The proposed research will seek to establish the role of proteins containing the vitamin K-dependent, calcium binding amino acid, gamma-carboxyglutamic acid (Gla) in the development of calcific cardiovascular disease processes. Gla has been shown to occur at the calcium binding sites of the vitamin K-dependent clotting factor proteins, and mediates the interaction with calcium and phospholipid necessary for proteolysis. Furthermore, Gla has also been discovered to be present in mineralizing bone in a unique protein known as osteocalcin. Gla is also present in normal kidney as well, and Gla is excreted in the urine, almost entirely as the free amino acid. The functional significance of the Gla proteins of bone and kidney is not as yet known, but may involve control of mineralization in bone and calcium transport in kidney. Gla synthesis in liver, kidney, and bone has been shown to occur as a post-translational vitamin K-dependent and bicarbonate-requiring reaction Vitamin K deficiency or antagonism results in decreased Gla synthesis, with resulting reduced calcium binding and in the case of the vitamin K-dependent clotting factors, anticoagulation. Gla has also been discovered to occur in pathologic calcifications including calcified atherosclerotic plaque, and calcific aortic stenosis. The objectives of this project are to isolate and characterize the Gla-containing proteins occurring in calcific cardiovascular diseases including; atherosclerosis, aortic stenosis and prosthesis calcification establish the role of Gla-containing proteins in the pathogenesis of these disease processes, detect and quantitate abnormalities in urinary Gla excretion in patients with calcific cardiovascular diseases. If Gla-containing proteins and vitamin K-dependent processes can be shown to be crucial to the development of calcific cardiovascular disease processes, then vitamin K antagonism with warfarin or related drug might favorably alter the course of these disorders.